Firefighters will link two fires in the NSW Blue Mountains in an effort to prevent a 'mega-fire' forming.

Queensland fire-fighters will join in the ongoing battle in NSW. This rural fire-fighter from Grose Vale is part of a backburn operation at Bilpen, in the Blue Mountains. Picture: Sam Mooy Source: News Limited

QUEENSLAND'S first fire ban of the season has been issued as 100 local fire-fighters today head south to NSW to help battle the state's blaze.

Authorities have issued a fire ban beginning midnight Wednesday for Fraser Coast, Gympie, North Burnett, Cherbourg, Bundaberg and South Burnett, with firefighters warning of perfect conditions for blazes to start and spread quickly.

Firefighters also are warning of dangerous conditions in the Channel Country as searing heat and gusty winds are recorded.

The call for help came late Monday afternoon after the New South Wales fire service reviewed maps, severe weather conditions and the fatigue of their crews.

"They were getting the latest weather updates and their aerial view of where the fire has extended to and finalising plans for Wednesday and they looked at their crews on the ground and made a call," he said.

The Queensland urban crews will work in the Sydney suburbs while the rural crews will be further inland, such as the Blue Mountains, with the fires expected to worsen on Wednesday.

At least 10 fire fighting vehicles will also go down to Sydney for the urban crews to operate.

The fire fighters are predominantly from the south-east corner of the state.

Assistance Commissioner Gallant said the deployments would not leave Queensland resources short.

"We plan for that and take a few from different brigades. We are in the middle of our fire fighting season here and we are aware of that but our conditions, particularly in the south-east, aren't terrible so our crews in the south-east haven't been flat out where as the north coast have been busy so we haven't taken from there."

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